closed loop

[pass1over]

So I was going to build a HoB closed loop for my 75gal and had it all planned out ... until I had an idea.

Instead of putting the pump outside the tank and pumping the water to it, then back up into the tank. Would it be possible to put the pump inside the tank (its submersible) and just run a section of pvc up, T at the top and branch how I want it?

Are there any negatives to putting the pump inside the display tank (it will be all hidden by rock), or is building a HoB like Melev's the way to go?

[trigger05]

you can do it, but it defeats one purpose of having a closed loop system: no pumps inside the tank.
also, how do you plan on holding the plumbing in place?
i would rather do the HOB closed loop like you had planned in the first place

[ChrisOz]

I just built Melev's SCWD closed-loop with the Mag 7 outside the tank and it's working fantastic... but I agree, for mounting and sustainability purposes, external pump is the way to go. Alternatively, do you have a sump... and would it be possible to just up the return pump GPH (unless it's already up there) and use the SCWD on that?

[pass1over]

his plumbing isnt being held in place by anything at all, its all relying on the pump as a base.

the only issue I can see with having the pump in the tank is heat. Doesnt the water pick up heat from the pump even when its external? Would it be significantly less heat added to the tank if it was external.

One issue im having is, there is nowhere to put the pump if I do a HOB closed lo0p like that. I would have to build some sort of platform and attach it to my existing stand.

ChrisOz~ flow from return pump from sump is open as much as my overflow will allow.

[hollback]

You mentioned the main issue which is heat transfer from the pump being submerged. You are correct that heat still transfers to the water column when the pump is ran externally but far less then when the pump is internal. The other big issue is servicing the pump. Having it internally, burried behind rock and coral would require some major tank shuffling to get to the pump. Keep your pump external.

I have a closed loop on my 75 with a Sequence Dart feeding a OceanMotions and I love it.

[pass1over]

im gonna run some experiments with the pump I intend to use for the CL.
Going to put it in my sump and monitor the temperature to see how much its gonna add. My g/f likes to keep the house cold, so it might not matter.

I have thought about the issue of accessing the pump once its in the tank. I think I can set it up in a way that minimal rock would have to be moved to get at it.